NAME
MorboDB - In-memory database, mostly-compatible clone of MongoDB
VERSION
version 1.000000
SYNOPSIS
use MorboDB;
# MorboDB usage is meant to refelect MongoDB usage
my $morbo = MorboDB->new;
my $database = $morbo->get_database('my_database');
my $collection = $database->get_collection('users');
my $id = $collection->insert({
username => 'someguy98',
password => 's3cr3t',
email => 'email at address dot com',
});
...
DESCRIPTION
MorboDB is an in-memory database, meant to be a mostly-compatible clone
of Perl's MongoDB driver, in such a way that it can be used to replace
or even supplement MongoDB in applications where it might be useful.
USE CASES
An in-memory database can be useful for many purposes. A common use case
is testing purposes, where using a "physical" database might be onerous.
You can already find a few in-memory databases on CPAN, such as MMapDB,
DB_File (has optional support for in-memory databases) and KiokuDB
(which has an in-memory hash serializer). I'm sure there are others
more.
I decided to develop MorboDB for two main purposes:
* MongoDB disaster fallback: at work I am currently developing a very
critical application that uses MongoDB (with replica-sets setup) as
a database backend. This application cannot afford to suffer
downtimes. The application's database has some constant data (not
too much) that shouldn't change which is completely required for it
to work. Most of the data, however, is dynamically written due to
user's work and is not as important, so it wouldn't matter if the
database won't be able to take such writes for some time.
Therefore, I have decided to build a fail-safe: when the application
is launched (actually I haven't decided yet if on launch or not),
the constant data is loaded into MorboDB, which silently waits in
the background. If for some reason the MongoDB database crashes, the
application switches to MorboDB and the application continues to
work - the users don't even notice something happend. Since MorboDB
provides mostly the same syntax as MongoDB, this isn't very
far-fetched codewise.
* Delayed writes and undos: I am also working on a content management
system in which I want to allow users to undo changes for a certain
duration (say 30 seconds) after the changes have been made. MorboDB
can work as a bridge between the application and the actual MongoDB
database (or whatever actually). So the data will only live in
MorboDB for 30 seconds, and if the user decides to undo, the data is
removed and nothing happens. Otherwise, the data is moved to MongoDB
after the 30 seconds are over.
MOSTLY-COMPATIBLE?
As I've mentioned, MorboDB is *mostly-compatible* with MongoDB. First of
all, a lot of things that are relevant for MongoDB are not relevant for
in-memory database. Some things aren't supported and probably never
will, like GridFS for example. Otherwise, the syntax is almost
completely the same (by relying on MQUL), apart for some changes
detailed in both "NOTABLE_DIFFERENCES_FROM_MONGODB" in MQUL::Reference
and "INCOMPATIBILITIES WITH MONGODB".
I have provided most methods provided by relevant MongoDB modules, even
where they're not really implemented (in which case they either return 1
or an undefined value). Read the documentation of MorboDB's different
modules for information on every method and whether it's implemented or
not. These methods are only provided to make it possible to use MorboDB
as a drop-in replacement of MongoDB where appropriate (so you don't get
"undefined subroutine" errors). Please let me know if there are methods
you need (even unimplemented) that I haven't provided.
Note that autoloading of database and collection objects has been
deprecated since version 1.0.0, in accordance with MongoDB.
STATUS
This module is beta software, not suitable for production use yet. Feel
free to test it and let me know how it works for you (of course, not on
production), I'd be happy to receive any bug reports, requests, ideas,
etc.
OBJECT METHODS
database_names()
Returns a list with the names of all existing databases.
get_database( $name )
Returns a MorboDB::Database object with the given name:
my $morbodb = MorboDB->new;
my $db = $morbodb->get_database('mydb');
get_master()
Not implemented, simply returns a true value here.
CAVEATS
Currently (not sure if this will change), MorboDB does not work in
shared memory, so if your application is multi-threaded, every thread
will have its own MorboDB container completely separate and unaware of
other threads.
DIAGNOSTICS
This module throws the following errors:
"You must provide the name of the database to get."
Thrown by "get_database()" if you don't provide it with the name of
the database you want to get/create.
CONFIGURATION AND ENVIRONMENT
MorboDB requires no configuration files or environment variables.
DEPENDENCIES
MorboDB depends on the following CPAN modules:
* boolean
* Clone
* Data::UUID
* Moo
* MQUL
* Tie::IxHash
INCOMPATIBILITIES WITH MONGODB
While I hope to make MorboDB as much of a clone of the MongoDB driver as
possible (syntax and usage-wise), some changes are inevitable.
Currently, only the most essential features of the MongoDB distribution
are implemented. That means you can insert documents as you would with
MongoDB, update documents and remove documents. You can find documents
and work with cursor pretty much the same, including sorting and other
cursor modifications.
Syntaxwise, any differences between MorboDB and MongoDB stem from the
usage of MQUL as the parser, so read the MQUL documentation for a list
of differences.
Another difference worth noting is with OIDs. In MongoDB, OIDs (the
automatic ones at least) are 24 characters long hexadecimal strings, and
are created by the MongoDB::OID module. In MorboDB, however, OIDs (also,
only the automatic ones) are 36 characters long UUIDs. This alone limits
your ability to use MorboDB alongside MongoDB in an application if you
perform queries on the "_id" attribute with known MongoDB::OID objects.
Other than that, this shouldn't really be a problem.
Featurewise, most differences should be missing or unimplemented methods
(and a few missing classes). I have taken some care not to miss any
methods provided by the MongoDB distribution, but I may have missed
some. Where methods are unimplemented, MorboDB will simply return a true
or false value (as appropriate). Please read the documentation of each
MorboDB module to learn what to expect from unimplemented methods (and
implemented methods of course).
Some features that are native to MongoDB itself (and not just the
MongoDB distribution on CPAN) will never be implemented in MorboDB (most
of them don't even make sense in an in-memory database).
Here's a (probably incomplete) list of MongoDB features missing from
MongoDB:
* Authentication
* Indexing (may be supported in the future, don't think so though)
* Replication
* Sharding
* Map/Reduce
* GridFS
INCOMPATIBILITIES WITH OTHER MODULES
None reported.
BUGS AND LIMITATIONS
No bugs have been reported.
Please report any bugs or feature requests to "bug-MorboDB@rt.cpan.org",
or through the web interface at
.
SEE ALSO
MongoDB, MongoDB::Connection, MQUL, MQUL::Reference.
AUTHOR
Ido Perlmuter
LICENSE AND COPYRIGHT
Copyright (c) 2011-2013, Ido Perlmuter "ido@ido50.net".
This module is free software; you can redistribute it and/or modify it
under the same terms as Perl itself, either version 5.8.1 or any later
version. See perlartistic and perlgpl.
The full text of the license can be found in the LICENSE file included
with this module.
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